Glass lasers were invented in 1961 (Snitzer E., "Optical Maser Action of Nd.sup.3+ in a Barium Crown Glass," Phys Rev., 1961, 7, p 444) and are now widely used. Glass lasers are advantageous because they have high gain, long fluorescence life times and can be simply made in a variety of geometries.
There is a reported observation of visible laser action from a samarium doped crystal (Kazakov B. N., Orlov M. S., Petrov M. V., Stolov A. L., Tkachuk A. M.; "Induced Emission of Sm.sup.3+ Ions in the Visible Region," Opt. Spectrosc (USSR) 1979, 47, p 676-677). However, laser emission due to the .sup.4 G.sub.5/2 to .sup.6 H.sub.9/2 transition in Sm.sup.3+ ions has not previously been observed in any material, particularly glass.